Any idea if I can somehow watch these videos with free software? With gnash in debian unstable I just get warning that never version of player is required.

Not sure if h.264 needs a nonfree codec or not. I'd try mplayer and
the ?ikiwiki swarm.avi if I were you, not the flash stuff.
I could put the ogg back up, but it was very large, and significantly bad
quality. Video quality matters a lot for these animations as they have a
lot of small text. --Joey